Sashless window structure and lock



Feb. 1, 1955 E. PIERSON 2,700,801

SASHLESS WINDOW STRUCTURE AND LOCK Filed Feb. 13, 1951 United States Patent O SASHLESS WINDOW STRUCTURE AND LOCK Ernest Pierson, Eureka, Calif.

Application February 13, 1951, Serial No. 210,721

14 Claims. (Cl. 20-52) This invention relates to sashless windows, generally of the type shown in my United States Letters Patent No. 2,530,724 of November 21, 1950.

One of the objects of the present invention is the provision of a sashless window in which there are two panes of glass adapted to slide one over the other to open position and in which window a simple and economical means is provided independently of the frame for automatically spacing the panes apart, except along one of their corresponding edges, during sliding movement, and which window also includes means for moving said panes to tight overlapping relationship along one of their adjacent edges when they are moved to closed position.

Another object of the invention is the provision of improved means in a sashless window for locking said window closed.

A still further object of the invention is the provision of improved means in a sashless window for locking such window in partially open position.

Still another object of the invention is the provision of improved means in a sashless window that functions to lock the window in partially open or in closed position, and that also provides a handle for grasping for opening the window.

Sashless windows permit the passage of noticeably more light than windows having panes of the same size, but which require sash. Also in sashless windows there is no break across the window such as is formed by sash where the panes overlap. Thus sashless windows afford a far better view than where the panes are in sash. The locking of sashless windows provides a problem, as does the provision for opening the windows.

While the notching of the glass to provide nger grips may be used, the glass is not suticiently thick to give a very secure hold, and there is the ever present likelihood that the iinger nails will be injured.

The locking of sashless windows in partially open or in closed position is difficult. One window may be blocked by dropping an element across one of its edges so it cannot be opened, but this presents the objection that the glass may be chipped where it strikes the obstruction.

With the present invention, both of the above objections have been overcome in a manner that is secure and in which no injury can occur to the linger nails or to the glass, and the lock is simple and cannot be successfully tampered with or broken from outside the building without breaking the glass.

Other objects and advantages will appear in the description and in the drawings.

In the drawings:

Fig. l is a view of the sashless window from inside the room, the frame being indicated secured to the studding, and no walls being on the latter.

Figs. 2, 3, 4, are enlarged fragmentary, sectional views respectively taken along lines 2 2, 3--3, 4-4 and 5 5 of Fig. l, but are restricted to the window frame and to the glass pane and parts carried thereby. The studding and building structure around the frame, as seen in Fig. l are omitted.

Fig. 6 is a fragmentary side-elevational view of the part shown in Fig. 5.

Fig. 7 is a sectional view taken along line 7--7 of Fig. 6.

Fig. 8 is an enlarged fragmentary sectional view similar to that of Fig. 7, but with the locking device shown in elevation and with the Window open.

In detail, referring to Fig. l, the frame of the present invention is rectangular, having vertical jambs 1, 2, a sill 3 and a head piece 4. The jambs 1, 2 in the present instance may be secured directly to studs 5 with the head piece 4 secured directly to the head element 6, which, in turn is secured to studs 7 that are between studs 5. The ends of the head element 6 are secured to studs 5. The sill 3 may be supported on blocks 8 that in turn are on a sill element 9 that is secured to its ends to studs 5 and intermediate its ends to intermediate studs 10. Secured against the opposedly facing sides of studs 5 (which are through studs extending from the ceiling to the oor) are auxiliary studs 11, 12 respectively above and below the ends of the head element 6 and sill element 9, and blocks 13 may be between the ends of the sill 3 and the ends of the sill element 9.

By the above structure, the window frame becomes a structural part of the wall in which the window is positioned. It strengthens the wall, whereas in conventional structure the jambs are not secured to the studs and neither is the head piece or sill secured to the studs or to the head and sill elements in a manner to contribute to strengthenng the wall.

In the present invention, the sill 3 is formed to provide an upwardly opening channel or groove 15 (Figs. 5, 7, 8) that is of sufficient width to receive therein the lower marginal portions of a pair of vertically extending glass panes 16, 17. The outer side 18 of the channel or groove 15 may be cut away at its opposite ends as at 19 (Fig. 2) to provide for drainage of water from the groove. lt is obvious, of course, that the channel 15 may be formed of metal or of wood, or may be a liner secured in the groove. The term groove or channel as here used is intended to cover any of these structures.

The jambs 1, 2 are respectively formed to provide opposedly opening grooves 21, 22 (Fig. 2). The left hand pane as seen in Figs. l, 2, is pane 17 and its lett marginal portion is adapted to snugly tit in the groove 21. The right marginal portion of the right hand pane 16 is adapted to enter the groove 22. However, the sides of groove 22 preferably taper slightly to the bottom. Thus the width of the groove at its open side is wider than the width at the bottom. This bottom width is equal to the thickness of the pane 16, therefore the right edge of the pane may readily enter groove 22, and as it slides to a tight seat against the bottom of the groove the sides of the groove will guide it to said bottom. This structure facilitates the entry of the edge of the pane 16 into groove 22 and also holds the pane against rattling in the groove when the window is closed. As will be later explained, the bottom groove 15 is slightly wider than the thickness of the two panes, but as the sides of groove 22 guide the right hand edge of the pane 16 to a tight seat no difficulty is encountered in sliding the pane 16 into groove 22.

The head piece 4 is formed with a groove that has different depths at different places therealong and the upper marginal portions of panes 16, 17 extend into said grooves. However, inasmuch as the two panes are in slidable engagement with each other along their upper edges they will be in the same groove 25 (Fig. 4). Pane 17, which is normally stationary, is the outermost pane relative to the inside of the room. Both panes are preferably of the same height and Width, and as the bottom of the bottom groove 15 supports the panes at substantially the same level, their upper marginal portions will extend the same distance into the upper groove 25.

Directly over pane 17 the bottom of the upper groove 25 terminates at the level 26 which is substantially even with the upper edge of pane 17, but over the portion in which pane 16 is adapted to slide when the window is opened, the bottom of the groove terminates at level 27 which is as much deeper than level 26 as the depth of the lower groove 15, and slightly deeper. When the pane 16 is in closed position, the bottom 28 (Fig. 3) of groove 25 over the portion of the pane that extends between the jamb 2 and the point where panes 16, 17 rst start to overlap at the center of the window opening is at about the same depth as the bottom portion 26 over pane 17.

By the above structure, both panes 16, 17 may readily be lifted out of the frame in succession, with pane 16 first, when pane 16 is slid to open position below the bottom 27. After pane 16 is out, the pane 17 may be moved to below bottom 27 of groove 25 and then lifted out. But in any other position of the panes except when the window is opened, the panes are not removable from the frame, The reverse operation will fit the panes 1n the frame.

As already pointed out, the panes 16, 17 should not touch each other when they are slid relative to each other, nor should there be any seal (other than close engagement between the panes) at their overlappmg portions. The overlapping zone is indicated at 30 (Fig. 1) and 1s also clearly seen in Fig. 5.

Carried by pane 16 adjacent its lower edge, but spaced above sill 3, is a bolt or screw 31 (Fig. 7). This bolt extends through an opening formed in pane 16, which opening is closely adjacent the zone 30 or free vertical edge 32 of pane 17 when the window is closed. Bolt 31 has a relatively at circular head 33 of convex contour. When the panes 16, 17 are closed and are -1n engagement at the Zone 30 where they overlap, it is quite obvious that the pane 16 cannot be slid to open position because of the projecting head 33. However, if the lower edge of pane 16 is slightly moved inwardly in the direction of the room so as to be against the side of groove that is at the room side, then the pane 16 may be slid to open position, and when this occurs the panes cannot touch each other because of head 33. Head 33 is of brass, preferably, so is relatively soft, and its line contact with the pane 17 will not scratch nor leave a mark on said pane 17.

From the above, it is obvious that even were the upper groove to be of the same depth as level 26 throughout the length of the head piece, so that pane 17 could slide in the frame,iit would be held against such sliding by the head 33 when the panes were held together in overlapping relation at zone 30.

A nut 35 on bolt 31 at the inside of the pane 16 will secure the bolt tightly to the pane with head 33 tight against the outer side of pane 16.

Swingably supported on the bolt 31 is a plate or leaf 36 that depends from said bolt. The leaf 36 is preferably of spring metal and a screw 37 threaded into the end of the bolt, with a washer 38 between the screw head and the bolt, secures the leaf against removal from the bolt. Also, the bolt cannot be manipulated by head 33 to release it as long as the leaf 36 is held on the bolt.

On the sill 3 at the room side of the groove 15 is secured an elongated plate or strip 40 (Fig. 5). This may b secured to the sill by any suitable means such as screws 4 One edge of strip 40 is cut away to provide a recess 42 that opens toward the pane 16, and the ends 43 of the recess may be square. Strip 40 and the said recess are symmetrical at opposite sides of a central line normal to the length of the strip so the end to end position of the strip is unimportant provided the strip extends longitudinally of the groove 15 with the recess opening toward the groove. The sill is also eut out below said recess and below strip 40 beyond the ends of said recess to the groove 15 (Fig. 7).

The strip 49 is secured to the sill parallel with the groove 15 leaving a substantial space between the edge of the strip nearest the pane 16 and the groove, and said strip s positioned at a point between jambs 1, 2 so that a point on the edge of the strip about midway between the recess and end of the strip nearest jamb 2 will be about where the lower edge of leaf 36 would fall when the leaf hangs freely from the bolt 31.

Leaf 36 is of substantially greater width than strip 40 and its edge nearest the window is close to tlze latter. A downward extension 45 (Fig. 7) on leaf 36 is adapted to extend past the strip 40 and the lower end of said extension 45 has a lateral projection 46 that is adapted to extend below the strip 40. However, said projection may be swung upwardly through the recess 42 in said strip only when the window is closed, but until said leaf is so swung the pane 16 cannot be moved at its lower edge away from pane 17 to permit the head 33 of bolt 31 to clear the edge of pane 17.

In this respect it is pertinent to note that the extension 45 where it passes between the pane 16 and the edge of strip 40 between recess 42 and jamb 2 functions to hold the panes 16, 17 close together at zone 30 so that no leakage of water will occur at said zone, and so that there will be no rattle. The edge 48 of strip 40 past which the extension 45 projects is parallel with the pane 16, hence the leaf cannot be jiggled out of its vertically extending position by manual jggling of the pane 16. If edge 48 were not parallel with the pane, the leaf would tend to swing so as to bring the projection 46 below the recess 42 if the pane were jiggled, but this cannot occur where said edge is parallel with the pane.

Heretofore considerable dificulty has been encountered in providing a universally satisfactory means for sliding the pane 16. If the pane is notched, to give a finger grip, the notch is necessarily so shallow that the finger nails would be likely to be injured. The provision of a handle specifically for that purpose would objectionably obstruct the vision and would weaken the glass. By providing the bolt 31 and the cylindrical portion 50 of leaf 36 that surrounds the bolt, the locking means functions to provide a handle for opening the window.

The pane 16 is locked in fully closed position by swinging leaf 36 from the dot-dash line inclined position 55 in Fig. 6, downwardly and counterclockwise to full line position, so that the projection 46 will swing past the edge of plate 40 adjacent groove 15 to the full line position in Fig. 5. The neck of extension 45 will tightly cngage the edge of plate 40 at the right of recess 42, as seen in Figs. 5, 6, and the marginal portions of the panes at zone 30 will be in tight engagement. Also the right hand edge of pane 16 will fit closely in the bottom portion of recess 22 in jamb 2 and the head 33 of screw 31 will be closely adjacent edge 32 of pane 17. The panes 16, 17 are quite rigid, firm, and tight relative to each oltherdand to the frame when the window is locked fully c ose In order to lock the window in partially open position, the swinging leaf 36, or locking element, is swung clockwise from the full line position of Fig. 6 until the restricted neck portion of extension 45 above projection 36 is in the recess 42 along the edge of plate 40. When in this position, the pane 16 can be moved away from pane 17 a sufficient distance to permit the pane 16 to slide toward open position (head 33 being between the panes 16, 17). However, the lateral projection 46, being below plate 40 along the bottom of recess 42 cannot pass the plate, and when the window reaches the point where the leaf 50 is in dash line position 56 (Fig. 6) the window will be locked against opening any further. No amount of manipulation can release the leaf 36 from its locking engagement with the plate 40 until the window is fully closed, hence any one outside the room cannot so manipulate the leaf by a wire or other instrument as to fully unlock the window.

It may here be noted that the groove 28 above pane 16 could be the full depth of recess 27 if desired, since the projection 46 on the leaf 36 would prevent the pane from being lifted out of groove 15 if the window is locked.

I claim:

1. A sashless window structure comprising a pair of rectangular window panes, a centrally open frame supporting said panes therein for relative movement from a closed position closing the central opening in said frame with said panes in parallel planes relatively offset to one another and with one of their marginal portions in overlapping face to face engaging relationship to an open position in which said central opening is partially uncovered by one of said panes and in which portions of said panes in addition to said marginal portions are in overlapping relationship, and a projection carried by one of said panes closely adjacent the free edge of the overlapping marginal portion of the other pane engageable with said other pane upon said relative movement for spacing one of the corresponding edges of said panes apart and thereby moving said panes out of said face to face engaging relationship.

2. A sashless window structure comprising a pair of rectangular window panes, a centrally open frame supporting said panes therein for relative movement from a closed position closing the central opening in said frame with one of their marginal portions in overlapping face toface engaging relationship to an open position in which sa1d central opening is partially uncovered by one of said panes and in which portions of said panes in addition to said marginal portions are in overlapping relationship, means carried by one of said panes engageable by the other pane upon said movement to open position for moving the said panes out of said face to face engaging relationship, said means having a locking element movably secured thereto, a plate carried by said frame, said element being movable into engagement with said plate for locking said panes against said relative movement and for holding said marginal portions in said face to face engaging relationship.

3. In a sashless window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jambs, a sill and a head piece, said panes being supported generally vertically on said sill closing said opening with one of the vertical edges of said panes in overlapping engaging relationship about centrally of said opening and with the other vertical edges of said panes against said jambs; one pane of said pair being movable over the other away from the jamb engaging its vertical edge, and means carried by said one pane engageable with said other pane at a point adjacent the lower edges only of said panes for moving said panes apart at their lower edges for tilting one of said panes during said movement.

4. In a sashless window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jambs, a sill and a head piece, said panes being supported generally vertically on said sill closing said opening with one of the vertical edges of said panes in overlapping engaging relationship about centrally of said opening and with the other vertical edges of said panes against said jambs; one pane of said pair being movable over the other away from the jamb engaging its vertical edge, and means carried by said one pane engageable with said other pane at a point adjacent the lower edges of said panes for moving said panes apart at their lower edges during said movement, said means being a projection on said one pane extending over the vertical edge of the other pane that is at said overlapping marginal portions when said panes are in a position closing said opening, and locking means for releasably holding s'aid projection in said position extending over said vertical edge for locking said panes in their position closing said opening until said locking means is released.

5. In a sashless Window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jambs, a sill and a head piece, said panes being supported generally vertically on said sill closing said opening with one of the vertical edges of said panes in overlapping engaging relationship about centrally of said opening and with the other vertical edges of said panes against said jambs; one pane of said pair being movable over the other away from the jamb engaging its vertical edge, and means carried by said one pane engageable with said other pane at a point adjacent the lower edges of said panes for moving said panes apart at their lower edges during said movement, said means being a projection on said one pane extending over the vertical edge of the other pane that is at said overlapping marginal portions when said panes are in a position closing said opening, and locking means for releasably holding said projection in said position extending over said vertical edge for locking said panes in their position closing said opening until said locking means is released, said locking means including an element movably connected with said projection and a member on said sill releasably engageable by said element. 6. In a sashless window structure having a pair of rectangular window panes and a frame provided with a central opening in which they are supported for horizontal sliding movement of one pane over the other from a closed position closing the central opening to open position and vice versa and in which closed position one of their vertical marginal portions along one of their vertical edges are in overlapping relationship substantially centrally of said opening and said frame including a sill so supporting said panes; a member extending through said one pane adjacent to and over the lower end of the vertical edge of the other pane at their said overlapping portions and secured to said one pane for movement therewith to a position between the lower portions of said panes spacing them apart when said one pane is slid on said sill to open position, locking means respectively secured to said sill and to said member movable into locking relationship locking said one pane in partially open position against further movement toward open position upon movement of said head to said position between said panes. j

7. In a sashless window structure having a pair of rectangular window panes and a frame provided with a central opening in which they are supported for horizontal sliding movement of one pane over the other from a closed position closing the central opening to open position and vice versa and in which closed position one of their vertical marginal portions along one of their vertical edges are in overlapping relationship substantially centrally of said opening and said frame including a sill so supporting said panes; a member extending through said one pane adjacent to and over the lower end of the vertical edge of the other pane at their said overlapping por tions and having a head projecting across the vertical edge of the pane at the said overlapping marginal portions and secured to said one pane for movement therewith to a position between the lower portions of said panes spacing them apart when said one pane is slid on said sill to open position, locking means respectively secured to said sill and to said member movable into locking relationship locking said one pane in partially open position against further movement toward open position upon movement of said head to said position between said panes, said locking means being also movable into locking relationship locking said overlapping marginal portions in said engaging relationship when said panes are moved to said closed position thereby preventing said head from said movement between said panes.

8. In a sashless window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jams, a sill and a head piece, said sill and head piece being respectively provided with opposedly opening grooves in which the upper and lower marginal portions of said panes extend with the panes supported on the bottom of the groove in said sill for sliding of one pane over the other, said jambs being provided with opposedly opening grooves in which the marginal portion along one of the vertical edges of each pane extends when said panes are in a position closing said opening, the marginal portions along the other vertical edges of said panes being in overlapping face to face engagement across the central portion of said opening when said panes are in said closed position, the groove in said head piece being substantially equal to the combined thicknesses of said panes and the groove in said sill being wider than the combined thickness of said panes to permit the lower edge of said one pane to move transversely in said groove away from the lower edge of the other pane, means on said one pane closely adjacent said overlapping portions engageable with the lower portion of said other pane for spacing said panes apart at their lower edges only during said sliding of said one pane over the other.

9. In a sashless window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jambs, a still and a head piece, said sill and head piece being respectively provided with opposedly opening grooves in which the upper and lower marginal portions of said panes extend with the panes supported on the bottom of the groove in said sill for sliding of one pane over the other, said jambs being provided with opposedly opening grooves in which the marginal portion along one of the vertical edges of each pane extends when said panes are in a position closing said opening, the marginal portions along the other vertical edges of said panes being in overlapping face to face engagement across the central portion of said opening when said panes are in said closed position, the groove in said head piece being substantially equal to the combined thicknesses of said panes and the groove in said sill being wider than the combined thickness of said panes to permit the lower edge of said one pane to move transversely in said groove away from the lower edge of the other pane, means on said one pane adjacent said overlapping portions engageable with the lower portion of said other pane for spacing said panes apart at their lower edges during said sliding of said one pane over the other, the sides of the groove in the jamb adapted to receive the vertical edge of said one pane y'being convergently extending toward the bottoni of said groove and the width of said last mentioned groove at its bottom being equal to the thickness of said one pane whereby the said vertical edge of said sill and on said member, said locking means being against rattling when said one pane is moved to closed position.

l0. In a sashless window structure having a pair of rectangular window panes and a centrally open frame including vertically extending jambs, a sill, and a head piece, said sill having a groove formed therein in which the lower marginal portions of said panes extend with the lower edge of one pane slidable longitudinally thereof in the bottom of said groove; said panes being in engagement with each jamb along one of their vertical edges when said panes are in closed position with the marginal portions along their other vertical edges in overlapping face to face engagement at the center of said frame, said lower groove being of suicient width to permit the lower edge of said one pane to move away from the lower edge of the other pane when said one pane is slid in said groove away from the jamb engaging its said vertical edge, a member extending through said one pane adjacent to but spaced above its lower edge and closely adjacent said overlapping marginal portions having a head projecting across the vertical edge of the pane at the said overlapping marginal portions, said head being engageable with said other pane upon said sliding of said one pane for movement to a position between said panes spacing their lower edges apart in said groove, locking means respectively on said sill and on said member, said locking means being movable relative to each other into and out of engaging relationship with each other for holding said lower edges of said panes against separation when said locking means is in said engaging relationship, whereby said head will engage the vertical edge of said other pane over which it extends to prevent said sliding of said one pane to open position.

ll. A sashless window structure comprising a pair of vertical jambs, a sill and a head piece defining the sides, bottom and top of a vertical rectangular, centrally open frame, opposedly opening parallel grooves respectively provided in said head piece and said sill, a pair of rectangular vertically extending window panes supported on their lower edges on the bottom of the groove in said sill and extending into the groove in said head piece at their upper edges, said lower groove being of uniform width and depth throughout its length to permit sliding one pane of. said pair within said frame from a closed position with one of the vertical marginal portions of said panes along one of their vertical edges overlapping each other at the center ot the frame opening and with their other vertical edges in engagement with said jambs respectively to an open position in which said panes substantially fully overlie each other in one half of said frame, the bottom of the groove in said head piece over said one pane in said one half of said frame being of sufficient depth to permit lifting said one pane suiiiciently to elevate its lower edge completely out of said groove in said sill and the bottom of the remainder of said groove in said head piece in the other half of said frame and the portion of the groove directly over the other pane being close enough to the upper edges of said panes respectively to preclude elevating said panes a distance suticient to elevate their lower edges from said groove in said sill whereby neither of said panes can be removed from said frame except when the window is fully open with said one pane fully overlying the other, the portion of said groove in said head piece in which the upper edge of said other pane is positioned terminating at its end nearest said overlapping portion whereby said other pane will be secured in said frame against sliding longitudinally of the groove in said head piece.

l2. A sashless window structure comprising a pair of vertical jambs, a sill and a head piece defining the sides, bottom and top of a vertical rectangular, centrally open frame, opposedly opening parallel grooves respectively provided in said head piece and said sill, a pair of reetangular vertically extending window panes supported on their lower edges on the bottom of the groove in said `sill and extending into the groove in said head piece at their upper edges, said lower groove being of uniform width and depth throughout its length to permit sliding one pane of said pair within said frame from a closed position with one of the vertical marginal portions of said panes along one of their vertical edges overlapping each other at the center of the frame opening and with their other vertical edges in engagement with said jambs respectively to an open position in which said panes sub- `stantially fully overlie each other in one half of said fratrie, the bottom of the groove in said head piece over said one pane in said one half of said frame being of sufficient depth to permit lifting said one pane suciently to elevate its lower edge completely out of said groove in said sill and the bottom of the remainder of said groove in said head piece in the other half of said frame and the portion of the groove directly over the other pane being close enough to the upper edges of said panes respectively to preclude elevating said panes a distance sufficient to elevate their lower edges from said groove in said sill whereby neither of said panes can be removed from said frame except when the window is fully open with said one pane fully overlying the other, and means respectively carried by said one pane and by said sill for releasably locking said one pane in window closing and in partially open position as desired.

13. A window lock for a pair of sashless window panes that are slidable in a frame, one over the other, from a closed position with one of their marginal portions only in overlapping engaging relationship to an open position with one of said panes substantially fully overlying the ot er, comprising: a horizontal pivot pin, a plate having a horizontal edge, a locking element swingably supported on and depending from said pivot pin, said element extending from one side of said plate to the other and being in engagement with said edge the end of said element remote from said pivot pin having a projection thereon extending under said edge, and said projection being movable to a position out from under said edge upon swinging said element about said pivot pin and toward horizontal, means for securing said pivot pin to one of said panes, and means for securing said plate to said frame.

14. A window lock for a pair of sashless window panes that are slidable in a frame, one over the other, from a closed position with one of their marginal portions only in overlapping relation to an open position with one of said panes substantially fully overlying the other, said lock comprising: a horizontal bolt, means for securing said bolt to one of said panes, a locking element swingably supported on said bolt and extending radially downwardly therefrom, the end of said element remote from said bolt having a projection thereon extending in a direction generally axially of said bolt, a horizontal plate formed with a recess along one edge thereof, means for securing said plate to said frame at a level above said projection and with said recess opening outwardly toward said one pane, said element being swingable into and out of said recess about the axis of said bolt, and being engageable with said one edge of said plate when swung into and past said recess for urging said marginal portions into said overlapping relation, said projection underlying said plate when said element so engages said one edge.

References Cited in the le of this patent UNITED STATES PATENTS 1,695,903 Sawyer Dee. 18, 1928 2,027,753 Sawyer Jan. 14, 1936 2,188,023 Tomsche Jan. 23, 1940 2,430,124 Johnson Nov. 4, 1947 2,530,724 Pierson Nov. 21, 1950 FOREIGN PATENTS 114,476 Sweden 1945 

